New features

• Added generic functions endOf and startOf #283 Added generic endOf and startOf functions
• Adding moment.fn.isValid #306 Add moment.fn.isValid
• Add cached format functions for 3x faster formatting. #317 Cached formatting functions
• Add support for month/weekday callbacks in moment.fn.format #313 Add support for month/weekday callbacks in moment.fn.format
• Add singular/plural forms for durations and startOf/endOf? #296 Add singular/plural forms for startOf/endOf
• Feature/instance lang #332 Instance languages
• Support for two-letter days-of-week #262 Support for two-letter days-of-week

Bugfixes

• Moment.js overflows in parsing #235 Moment.js overflows in parsing
• utc(Number) not working #323 moment.utc(number) is broken
• NodeJS check gives a false positive when running QUnit #314 False positive when checking for NodeJS alongside QUnit
• Fix parsing/formatting of first century dates. #367 Parsing first century years and creating a moment with +-270,000 years in array
• Parsing String + Format doesn't handle timezone #371 Parsing moment.utc(string, format) was broken when the string had a timezone offset

Language updates

• Hungarian language with unit tests #318 Add Hungarian language
• persian language #316 Add Persian language
• Romanian localization #326 Add Romanian language
• Added Chuvash Language #305 Add Chuvash Language
• fixed minor for LLL format of Japanese #307 Minor fix for LLL format in Japanese
• Russian translations are incorrect #312 Fix month name nominative case in Russian
• Remove ordinal from TR translations #327 Remove ordinal from Turkish language
• Switch from TLD to two letter language code ? #293 Switch from TLD to two letter language code